Manufacture of artificial filaments or threads



March 6, H ok ET AL,

MANUFACTURE OF ARTIFICEAL FILAMENTS OR THREADS Filed June 25, 1930 FI J. FIGI 85 HENRY DREYFUS WILLIAM I. TAYLOR ENVENTORt;

ATTORN'EYb Patented Mar. 6, 1934.

UNITED STATES PATENT OFFICE MANUFACTURE OF ARTIFICIAL ma- MENTS a THREADS of Delaware Application June 25, 1930, Serial No. 463,659 In Great Britain July 20, 1929 3Claims.

This invention relates to the manufacture of artificial filaments or threads.

A process 'of manufacturing artificial filaments or threads from solutions of cellulose acetate or 5 other cellulose derivatives is described in U. S. Patent No. 1,602,125, the process including the step of leading the filaments or threads out of a casing in which they have been spun, and winding the filaments on suitable winding, or twisting and winding devices located outside the casing. U. S. Patent No. 1,731,317 describes a process of manufacturing artificial filaments or threads from similar solutions, the filaments or threads being twisted and wound continuously 1| with their production by means of cap-spinning devices which are preferably located outside the spinning chamber or casing. By the adoption of cap-spinning devices, extremely high speeds can be employed for twisting and winding the filaao ments or threads.

It has now been found that a high rate of production can be achieved in the manufacture of artificial filaments or threads when twisting and winding the filaments or threads by collecting them and forming them into packages in centrifugal boxes, provided the diameter of the boxes is small whereby the boxes may be rotated at a very high speed and rates of twisting comparable with those obtained by the use of cap-spinning devices may be reached. Thus, instead of the relatively low speeds of 5,000-6,0'00 R. P. M. which have constituted the maximum at which centrifugal boxes as heretofore constructed could be run, speeds of 12,000, 15,000, or even 20,000

R. P. M. or more may be used with centrifugal boxes according to the invention.

In order that the size of the yarn package produced in the box (as measured by the length of thread contained in the package) is not unduly 40 limited by the small diameter of the box, the axial length of the box may be increased so that packages of a size commensurate with those produced by cap-spinning devices may be obtained.

The yarn packages thus produced are in the 5 form of a cake or cheese of comparatively large length and small diameter, the traverse of the filaments or threads relatively to the box during Winding being, of course, approximately equal to the length of the box, Traversing of the filaments or threads to build the package may be effected either by reciprocating a guide which leads the filaments or threads into the box, or by reciprocating the box, in which latter case the guide may be maintained stationary.

Examples of dimensions which may be adopted in constructing centrifugal boxes according to the invention, though, of course, the invention is not in any way limited thereto, are 3, 4, or 5 inches for the diameter and 6, '7, 8 or 10 inches for the axial length or for the length of the package to be built. It is to be noted that the tendency to diminution in centrifugal force operating to draw the filaments or threads to the walls of the boxes due to the lessened radius adopted can be at least compensated and even exceeded by the increase in the force resulting from the higher or much higher speeds at which the boxes of lessened radius can be run.

Introduction of the filaments or threads into the box may be efiected in various ways. The spinning process constitutes a continuous operation and it is therefore necessary on starting up to pass the filaments 'or threads into the box without any delay or interruption which would result in an accumulation of filaments or threads and prevent the delivery of the filaments or threads to the box. The following methods and devices, which are given by way of example only, may be adopted to eflect the introduction of the filaments or threads. It is usual, for example, in the apparatus employed for dry-spinning artificial filaments or threads, to employ a waste or feed roller on which the filaments or threads are wound during any interval in the winding or twisting operation, such waste or feed rollers being shown in U. S. Patents Nos. 1,602,125 and 1,731,317 above referred to. The end of the filaments or threads is taken after the filaments or threads have passed round the waste or feed roller, or directly from the dryspinning chamber or from a precipitating bath, and the end is caused to enter the box and to come into engagement with a guide depending into the box, the end on leaving the guide being drawn to the wall of the box by centrifugal force. Building of the yarn package proceeds by the twisted filaments or threads being laid inside the box.

The end of the filaments or threads may be led into the box through a tube or guide down which a stream of water or other suitable liquid is caused to pass on starting up, the liquid stream carrying the end of the filaments or threads with it through the tube or guide. Alternatively, the end of the filaments or threads may be sucked into and through a tube or guide by the use of an ejector device operating in conjunction with or forming part of the tube or guide and using a fiuid stream. such as water or air.

A suitable ejector device comprises a double tubular member (preferably conical) forming an annular space to which compressed air is supplied. The air issues from one end of the device and exerts suction on a thread which has been brought'to the other end of the device, drawing the thread through the device and ejecting it therefrom into the centrifugal box. The ejector device is, of course, only required to operate for a brief space of time until the end of the thread passes into the centrifugal box, and it is con venient to provide a control for the fluid stream which can be actuated by the hand or foot of the operative without interfering with his manipulation of the thread. For example, a cook or valve for the supply of compressed air or other fluid to the ejector device maynormally be kept closed by a spring or the like and opened at the required time by a pedal, 01' by a lever arranged for actuation by the operatives hand, preferably by the hand used to introduce the thread to the ejector device. A tube or guide may also be used which is provided with a slit through which the filaments or threads are inserted. The tube or guide may be made into two parts so that the slit may be closed after insertion of the filaments or threads. A further form of device comprises a guide in the form of a spiral of sheet metal or other material, the device being arranged so that" the filaments or threads can be thrown or passed into an outer turn of the spiral and carried by the rotation of the centrifugal box to the centre of the spiral, which constitutes a tube-like guide. The base of this tube-like guide is so formed that the filaments or threads leave the guide at the same level round the edge of the guide, so ensuring uniform twisting.

The filaments or threads may, moreover, be threaded through a tube or guide and passed into the centrifugal box by applying to their end a relatively heavy mass which falls through the tube or guide and carries the filaments or threads with it.

In order to avoid electrification troubles arising by reason of the dryness of the filaments, which dryness. may be accentuated by the high rate of operation achieved by the use of the centrifugal box, lubricating or moistening devices may be arranged in proximity to the path of the filaments as they are passing from the spinning chamber to the centrifugal box. The lubricating or moistening may be carried out either before or after the filaments reach the feed roller. Other treatments, such as for example, sizing, may be given to the filaments or threads during their passage to the centrifugal box.

The invention is applicable to the twisting and winding of artificial filaments or threads'of cellulose acetate or other organic derivatives of cellulose, such as other esters of cellulose (e. g. cellulose formate, propionate, or butyrate) or ethers of cellulose (e. g. methyl, ethyl or benzyl cellulose), or of other artificial filaments orthreads, whether produced by the dry or evaporative method or by the wet or coagulation method.

The accompanying diagrammatic drawing serves to illustrate convenient forms of execution of the invention applied to the formation of filaments or threads of cellulose acetate or other cellulose derivatives by the dry-spinning or evaporative method of formation. In the forms 11- lustrated the filaments or threads in the course of their travel to the centrifugal boxes, are sized. In the form illustrated in Figures 1,-5 the filaments or threads are introduced into the centrifugal box by means of a guide formed or provided with an ejector, which ejector is arranged to operate only during the initial introduction of the filaments or threads into the centrifugal box.

Figures 6, 7 and 8 illustrate a modified form of guide which enables the filaments or threads to be introduced into the centrifugal box without the aid of an ejector or auxiliary means, the guide being formed in such manner that the thread can be carried automatically into its proper position in the guide bythe rotation of the centrifugal box.

In Figures 1-5 of the drawing,

Figure 1 is a sectional side view of the apparatus; v

Figure 2 is a front view of a part of the apparatus shown in Figure l;

Figure 3 shows on a larger scale the means shown in Figures 1 and 2 for or threads:

Figure 4 shows in section and on a.larger scale than Figures 1 and 2 the valve employed, for controlling the ejector; and

Figure 5 shows the ejector in section a larger scale than in Figures 1 and 2.

Referring to Figures 1-5, 1 is the metier casing divided into a number of spinning cells, 2, 2a, two of such cells being shown, but it is of course understood that any number of spinning cells can .be employed. The filaments 3, 3a are formed by extrusion of the spinning solutions into the respective spinning cells 2, 2a in the known manner, the cells being heated by steam heated pipes or coils 4 and 5 and a heated current of air being caused to pass upwards through the spinning cells. The filaments leave the cells 2, 2a via the respective guides, such as 6, and pass to the respective draw rollers 7, 7a. The filaments pass over the respective draw rollers '7, 7a back to the respective guides,'such as 8, thence again over the draw rollers and thence under the guides 9 and to and over the respective sizing rollers 10, 10a. The sizing rollers are rotated in baths 11. 11a containing any convenient or suitable sizing composition (such as is employed for the sizing of cellulose acetate and like artificial filaments or threads), whereby they pick up size from the baths and bring" the size into contact with the filaments. If desired or necessary the sizing 1Z5 baths 11, 11a may be heated by passing steam, heated water or the like through the pipe 12. From the rollers 10, 10a the sized filaments pass via the respective guides 13, 13a, which are placed substantially centrally over the respective guiding devices 14, 14a, and centrifugal boxes 15, 15a. From the guides 13, 13a the filaments or threads pass respectively to the guiding devices 14, 14a to the respective centrifugal box 15 wherein they are wound and twisted at a very high speed. The 185 centrifugal boxes are of small diameter, preferably between about 3 and 4 inches in diameter, and of relatively great axial length, e. g. 8-10 inches. They are rotated at a very high speed, such for instance as 15000-20000 or more R. P. M., by belts 16, 16a passing over their respective whorls and are traversed by means of a bar 17, the guides 14, 14a remaining stationary.

In order to introduce the filaments into the centrifugal box on first starting up or upon changing the centrifugal box, it is, of course, necessary to cause the end of the filament bundle to pass down and through the tubular guiding device 14 (or 14a as the case may be), and into the centrifugal box. Once in the centrifugal sizing the filaments 95 andonlOO box the filaments or threads are, of course, wound and twisted by the centrifugal action of their high speed of rotation caused by contact with the centrifugal box. The introduction of the filaments or threads into the box is eflected by means of the respective ejector devices 18, 18a. These ejector devices are fitted to or formed with the respective tubular guides 14, 14a. Each of the ejector devices (see Figure 5) is formed with a double conical member 19 forming an annular space 20, and means which are hereinafter described are provided for causing a blast of compressed air or other fluid to be supplied to the annular space.

To introduce the filaments into the centrifugal box the filaments are dropped into the cone 21 of the ejector device 18 (or into the cone 21a of the ejector device 18a as the case maybe) and a blast of compressed air or other fluid admitted to the annular space 20, which blast draws or sucks the filaments or threads through the apex 22 of the cone and blows or forces the filaments or threads through the tubular guide 14 (or 140 as the case may be) and into the centrifugal box 15 (or 15a as the case may be). As above indicated. the blast of compressed air or other fluid is only admitted to the ejector device during the introduction of the filaments to the centrifugal box, and for this purpose each of the ejector devices is connected via the respective pipes 23, 23a with a supply line or header 24 of compressed air or other fluid controlled by the respective valves 25, 2541. These valves (see Figures 1, 2 and 4) are arranged to be opened by depressing their respective pedals 26, 26a to lower the valve member (see 27, Figure 4) off its seat and to allow the blast of compressed air or other fluid to enter the annular space 20 and thereby introduce the filaments or threads into the centrifugal box in the manner above described. When the filaments have entered the centrifugal box the pressure on the pedal 26 (or 26a as the case may be) is released and the valves closed by means of springs 28, 28a acting upon the respective pedals.

As above mentioned, Figures 6, 7 and 8 illustrate the modified form of guide which may be usedin place of the ejector devices and tubular guides shown in Figures 1-5. This modified form of guide enables filaments or threads to be introduced directly into the centrifugal box and avoids the use of compressed fluids.

Figure 6 shows the guide in elevation, whilst Figures 7 and 8 are top and bottom views respectively of Figure 6.

Referring to Figures 6. 7 and 8, the guide is formed from a piece of sheet metal or the like folded round in the form shown and has a longitudinal slit or opening 29 from top to bottom of the guide. The device is formed with a ton e 30 connecting with the slit or opening 29 and is supported in position to depend into the centrifugal box by means of the supporting arm 31. To introduce the filaments from the guide and into the centrifugal box, the filaments are lead or thrown against the tongue 30 and allowed to fall into the centrifugal box. The rotating centrifugal box thereupon pulls the filaments against the tongue 30 which forces them through the longitudinal slit or opening 29 and into the bottom of the guide, the direction of rotation of the centrifugal box being, of course, in the same direction as the direction of entry into the guide. When in the guide the filaments or threads are guided into their correct position in traversing the centrifugal box by means of the end 32 of the guide.

What we claim and desire to secure by Letters Patent is:-

1. Apparatus for conducting artificial threads continuously with their production into a centrifugal box preparatory to their collection there in, said apparatus comprising a tubular guide with a double walled funnel shaped ejector device secured to and opening into its top, and means for supplying a fluid stream to said device, said stream being adapted to induce. a gaseous current which draws the thread into the device, and to forward the thread from the device to a centrifugal box.

2. Apparatus for conducting artificial threads continuously with their production into a centrifugal box preparatory to their collection therein, said apparatus comprising a tubular guide with a double walled funnel shaped ejector device secured to and opening into itstop, means for supplying a fluid stream to said device, and valve means operable against spring action to control said stream, said stream being adapted to induce a gaseous current which draws the thread into the device, and to forward the thread from the device to a centrifugal box.

3. In an apparatus for the winding and twisting of artificial threads continuously with their production, the combination with a centrifugal box of less than 5 inches in diameter and means for rotating said box at a speed of at least 12,000 revolutions per minute, of a tubular guide with a double walled funnel shaped ejector device secured to and opening into its top, and means for supplying a fluid blast to said ejector device adapted to convey the threads from the ejector device to the centrifugal box and to induce a gaseous stream to draw the threads into the ejector device.

HENRY' DREYFUS. WILLIAM IVAN TAYLOR. 

